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By H W. Scriba

The development and improvement of computer-based process simulation packages over the past 20 years has provided process engineers with a powerful tool to use in the design of complex metallurgical plants. The use of such modelling tools has enabled the design of process plants that minimise operating and capital costs whilst optimising plant efficiency and recovery. Almost every new project developed in the current market is underpinned by a simulation of the process. In line with engineering best practice this simulation should be based on laboratory/pilot plant test work results and sound assumptions. Any errors that are not identified in the development of the process simulation may have significant effects on the final design and operation of the processing plant. Developing a simulation of the process in a comprehensive, logical and auditable manner is thus essential in ensuring the simulation accurately represents the expected process plant behaviour. A methodology that ensures these requirements are met has been developed by SNC-Lavalin Australia and is described in this paper. The methodology includes the major review stages of data collection, model planning, model building and optimisation, model review, scenario testing and options development, and model reporting. All of these stages should incorporate comprehensive client interaction and review by a suitably qualified representative. In applying these methodologies SNC-Lavalin Australia ensures that the process simulation model developed can be confidently utilised in the design of the process plant, and in the estimation of operating and capital costs, whilst ensuring that engineering best practices are met.

Jan 1, 2008

By Koppe JC, Strieder AJ

The Rivera Crystalline Island (RCI) is an erosional window of the intracontinental Parana Basin that outcrops in the Rivera Department, north of Uruguay. RCI is made up mainly by Precambrian granites, metasediments and granite-gneisses. This island is crosscut by a dextral transcurrent shear zone system, the Rivera Shear System (RSS). The bulk strain ellipsoid was defined by previous work and has allowed the evaluation of shear dynamics. The geometry of the shear system is made up of two shear directions: E-W (P-shear), which turn right to NW-SE direction (R-shear), leading to the development of extensional bends. The shear zone system was developed in brittle-ductile to brittle regimes, under temperature conditions compatible with greenschist facies metamorphism. The shear zones are marked by an intensive fracture cleavage development. Mylonites develop only in narrow, discontinuous higher strain zones. Internally, the shear zones are dominated by intrusive rocks, mainly granites, dacites and diorites. Hydrothermal alteration has been developed in several areas.The economic significance of RCI is given by several small gold deposits, which have been exploited since 1869. One major new gold mine is under development, the San Gregorio Gold Mine. This gold deposit is locally controlled by a dilatant site where R-shear turns right to P-shear. Mine lithologies were deeply altered by hydrothermal fluids in the dilatant structure. This work presents the lineament-structural analysis carried out to identify similar structural patterns in all RCI sites favourable to host other gold deposits. The exploration program also considered remote sensing, geology, geophysical and geochemical survey.

Jan 1, 1997

By K Ehrig

Two irrefutable facts in geology and metallurgy are: ore deposits are comprised of variable mixtures of minerals which are systematically distributed throughout the deposit, and mineralogy exerts the primary control on metallurgical performance. If the distribution of process critical minerals can be quantified and mapped, then a logical assumption is that metallurgical performance can be predicted across the deposit.Olympic Dam is a +9 billion tonne Fe-oxide Cu-U-Au-Ag deposit which is hosted entirely within a magmatic-hydrothermal breccia complex consisting of over seventy ore and gangue minerals. Each has a unique set of metallurgical performance properties. Fortunately, 15 of the 70 minerals accounts for >98 per cent of the total rock mass.The mineral mapping journey commenced in the early drilling days shortly after the discovery of Olympic Dam in 1975. Geologists quickly recognised that the copper-iron sulphides had a predictable zoned distribution. However, geological models reflected the presence or relative abundances, not quantitative concentrations, of the minerals. This type of mineral mapping remained relatively unchanged for ~20 years and was of limited use outside of geology.Several things changed during the mid-1990s: assaying costs decreased significantly, instruments capable of automatically measuring mineralogy became readily available, the recognition of two quantifiable relationships at OD (ie mineralogy is a function of chemical composition (ie assays), and metallurgical performance is a function of assays, mineralogy, texture and process conditions. The linkage of metallurgical performance to mineralogy and mineralogy back to assays allows for every assayed sample in the resource model to be assigned mineral concentrations and metallurgical performance predictors. At Olympic Dam, block models (ie 3D maps) are routinely produced for 27 elements, density, 15 process critical minerals and greater than 50 metallurgical performance variables. These geometallurgy-enabled resource models are used for mine planning, process plant design and process optimisation studies. *This is an abstract only. No paper was prepared for this abstract.*

Sep 5, 2011

By D E. Tennant

In the fields of geotechnical engineering and slope management, various software packages are used to assess the behaviour or propensity for a slope to fail. Traditional kinematic analysis calculates the probability of failure of design sectors with respect to dominant structural set orientations. A novel methodology is provided here to view potential hazardous slope behaviour in 3D, allowing engineers to make informed decisions regarding various pit slope geometries. Apparent dips are calculated for every point in space with respect to every slope orientation of the entire pit surface/design, specifically in reference to bench and inter-ramp planar failure mechanisms. Implementing a proactive approach to slope design will not only lead to early mitigation of risk but can also add direct value by enhancing or improving upon slope angles for earlier access to ore. From a safety perspective, identification of unfavourably oriented slope geometries can be dealt with before failure occurs. This methodology relies on a strong understanding of the existing rock mass anisotropy, particularly behind the face, thereby removing some of the uncertainty surrounding pit design as well as presenting engineers with an additional means to manage risk.

Nov 29, 2022

Cominco Ltd's Polaris Mine in Canada's High Arctic has been successfully mining zinc ore in permafrost since 1981. Mining methods using frozen backfill have been the key to success. The mine is now producing about 60 per cent of the ore from pillars while maintaining high productivities. Annual ore production is just over one million tonnes providing more than 200 000 tonnes of zinc concentrate each year. Cominco Ltd has adapted management and operating practices to suit the harsh environment and the isolated site, and has shown that a profitable development can be carried out in the tough Arctic conditions, with minimum impact on the environment.

Jan 1, 1993

INDEX OF CONTENTSIntroductionThe slag samplesGranulated SlagGlass-spinel-magnetite-metallic leadRapidly Chilled SlagSlowly Cooled SlagSpinel - magnetite - zinc melitite (hardystonite) willemite - olivine -lead silicate - metallic lead - lead sulphide - copper sulphide - copper arsenide - nickel arsenide.ConclusionsIllustrationsINTRODUCTIONThis paper presents the results of a mineragraphic examination of representative samples of granulated lead blast furnace slags from the Port Pirie Smelter, and of slowly cooled samples of t:b.e same slags, undertaken at the request of the Broken Hill Associated Smelters Pty. Ltd., as part of the research programme of the Mineragraphic Section of the Commonwealth Scientific and Industrial Research Organization.THE SLAG SAMPLESThe chemical composition of the slags examined is given by the following three analyses of the granulated slags, supplied by the Broken Hill Associated Smelters (Table 1).

Jan 1, 1949

Segregation studies in ternary systems of glass ballotini, iron ore and coke particles (with size range of 1-8 mm in each) in filling and emptying a laboratory size Paul Wurth hopper are described. In-bin segregation is shown to be a function of the position in the hopper, the nature of the material and the feed composition. The in-bin results are correlated by the equation C = C0k, where C and C0 are the size compositions (wt per cent) in the hopper and feed respectively, and k is an experimentally obtained segregation constant. The results of now pallern measurements show that material discharges from the hopper according to the sequence; core now - wall now - scaffold now, where the latter represents stagnant material at the hopper wall that discharges last. Size segregation in the discharge stream from the hopper is shown to be a function of in-bin segregation and hopper now pallern. A method of predicting discharge segregation from these two sets of data is suggested. The results of the model studies are also compared with industrial data and these show satisfactory agreement. Discussion of the hitherto ignored effect of size segregation on hopper now rates, stoppages and other operating problems is also included.

Jan 1, 1985

By G King, Q Shu, W Cao, F Gyakwaa, H Singh, S Wang, M Huttula, T Fabritius

Metallurgical slag, such as refining slag, is essential to enhance or promote steel cleanliness. The CaO–MgO–Al2O3–SiO2 system is the primary source of oxides-based inclusions. It plays a vital role in applications in various pyrometallurgical processes. Numerous thermodynamic databases and physicochemical properties of slag studies mainly focus on quenched samples and measurements at room temperature. Consequently, the present study explored the physicochemical, structural properties and crystallisation evolution for CaO–MgO–Al2O3–SiO2 glassy slags via in situ hightemperature Raman spectroscopy and synchrotron X-ray diffraction. The study was carried out by synthesising CaO–MgO–Al2O3–SiO2 slag with varying Al2O3/SiO2 ratios. The results from the in situ high-temperature measurement demonstrated a pattern showing a transformation of a broad peak from the glassy matrix to crystalline peaks. The study showed crystallisation of dominant phases such as Ca2SiO4, Ca2Al2SiO7 and CaAl2O4 that correspond and are attributable to changes of structural units during in situ high-temperature measurements. The results further showed a correlation between an increase and transformation in crystalline phases observed from the spectra obtained from non-isothermal heating of the samples.

Jun 19, 2024

The City of KalgoorlieBoulder is situated approximately 600 kilometres to the east of Perth, and as the major regional centre of the Eastern Goldfields, supporting a population of approximately 25 000. The formation of Kalgoorlie Consolidated Gold Mines in 1989 brought the existing operating entities adjacent to the city under common ownership and management. The Joint Venturers forming the management company are Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy/Poseidon company).This traditional underground mining centre has been worked since 1893, yielding 40.5 million ounces of gold ore with an average head grade of TEN grams per tonne. Historically the heart of the operation has been the famous Golden We located on the Eastern perimeter of the city, in the area known as Fimiston. The other significant operations that form KCGM are the Mt Percy Open Pit and the Mt Charlotte Underground Operation.

Jan 1, 1992

By Tozawa K, Nishimura T, Sasaki K

Liquidus surfaces in a part of the systems ZnO-PbO-Si02 and ZnO-"FeO"-SiO 2 were constructed by the quenching method. The ex- periments were carried out in air in the system ZnO-PbO-Si02. In the part investigated the primary phases were three ternary compounds (PbO.ZnOòSiO2, 2PbOòZnO.2SiO2 and barysilite), three lead silicates, Zn2SiO4 and SiO2. Iso- therms on the liquidus surface of each primary phase field were determined from 750 to 1300¦C. In the system ZnO-"FeO"-SiO 2 the experiments were carried out in an atmosphere of purified nitrogen. In the part investigated the primary phases were Fe2SiO4, Zn2SiO4 and Si02. Iso- therms on the liquidus surface of each primary phase field from 1150 to 1300¦C and the ternary eutectic (1130¦C, 15.9% ZnO, 48.2% "FeO" and 35.9% Si02) were determined.

Jan 1, 1980

By H Zhang, S Li, J Song, Z Lv

In this paper, a method for extracting and refining metallic molybdenum using low-temperature ZnCl2- NaCl-KCl molten salt was proposed. The electrochemical behaviour of molybdenum ions in ZnCl2- NaCl-KCl molten salt was investigated in detail, and pure metallic molybdenum was collected on the cathode. The reduction and diffusion processes of Mo(V) ions in ZnCl2-NaCl-KCl molten salt were determined through a series of electrochemical methods. The diffusion coefficients and nucleation modes of Mo(V) ions were also studied, and electrolysis was conducted for a prolonged period at a constant current density. The results indicated that the electrode reduction of Mo(V) ions in ZnCl2- NaCl-KCl molten salt proceeds through a three-step reaction: Mo(V) → Mo(IV) → Mo(III) → Mo at 250°C. The Mo(V) → Mo(IV) reaction was reversible and diffusion-controlled, with a Mo(V) diffusion coefficient of 6.02 × 10-6 cm2 s-1. Additionally, the nucleation mode of Mo(V) ions was instantaneous nucleation. The products electro-deposited were confirmed of metallic molybdenum with a particle size of less than 1 μm.

Aug 21, 2024

By G Guy, J Summerville

Over the past five years in coalmine slope evaluation the application of 3D modelling has increased significantly as software has become more user friendly but also areas requiring evaluation have become increasingly complex. Often simplistic 2D Limit Equilibrium modelling and analysis has been poorly used to solve slope stability issues by back analysis and subsequent forward predictive analysis. A plane strain condition with slope movement perpendicular to the slope strike is assumed where in reality the problem is more complex. This often leads to a misinterpretation of the failure mechanism because the failure mechanism being modelled in 2D does not generally represent the actual failure mechanism observed in the pit, with 2D modelling often oversimplifying a slope. This paper presents a case study where the initial slope assessment and remedial design evaluation was undertaken as a 2D Limit Equilibrium model which led to an overly conservative and costly remedial solution being implemented. Subsequent modelling of the slope using both 3D Limit Equilibrium and Finite Element methods were able to provide a better understanding of the structural complexities associated and correlate well with slope monitoring data to create a more realistic outcome.

Nov 29, 2022

By Katsuyama K, Nag DK

Three aspects of rock mechanics, namely, in-situ stress estimation by acoustic emission (AE) method, strength of rock mass and role of chemicals to reduce the strength are covered. It is possible to detect the previously applied maximum stress by stressing a rock specimen to the point where there is a substantial increase in AE activity. This is known as Kaiser effect. From the AE signatures in the second and subsequent loadings, AE take-off point was identified more easily than in the first loading. In determining the compressive strength of rock mass, two factors have to be considered, namely, the size effect on the compressive strength of intact rock and the effect of discontinuities on the compressive strength of rock mass. Although a modified Bieniawski criterion gives best agreement with the triaxial test data, modifications have been suggested to Hoek-Brown criterion due to its popularity. It is possible to reduce the tensile strength of sandstone by saturating it with weak chemical solutions made with dodecyltrimethyl ammonium bromide, polyethylene oxide and aluminium chloride by up to 30%. In the case of compressive strength, there is no appreciable effect. The possible explanation is that the chemical solutions produce an effect on the strength of sandstone only when the failure mechanism is dominated by tensile mode.

Jan 1, 1998

The ore deposits investigated are composed primarily of hcmatite and can be grouped into three categories depending on the amount of leaching of silica and carbonate which has occurred from the original iron formation, and on the amount of recrystallization of the hematite. Minor constituents are magnetite. goethite, and quartz.Texturally. there are five different types of hematite, formed at different stages during the genesis of the ores.These are1. anhedral hematite grains formed by recrystallization of hematite already present in the original iron formation.2. hematite formed by martitization of euhedral magnetite, 3. massive aggregates of fine- to medium-grain hematite formed by recrystallization of (l) and (2).4. tabular or prismatic hematite grains occurring around the boundaries of the massive aggregates or martite euhedra. and in fractures and5. specular hematite. which is present in fractures in ore types (l) to (4).Minor and trace-element analyses, determined using an electron-probe microanalyser. indicated that only silica (less than 0·01 per cent) and cobalt (less than 0·002 per cent) were present in the magnetite and hematite from unaltered iron formation and in the hematite from the ores. Low concentrations of trace elements are typical of magnetite in ores formed as marine precipitates. On the basis of the analyses alone. it proved impossible to distinguish between the five hematite types. A determination of the variation in rare-earth trace element contents between iron oxides in the iron formation and iron oxides in the ores indicates that the rare earths were depleted during ore formation. A possible explanation is that they were removed in solution with silica as it was leached from the iron formation.

Jan 1, 1971

By K S. E, S C. Parker, T K. Kundu

Understanding the fundamental principles governing the reactions at surfaces has always been the goal of theoretical surface science. The atomistic simulation techniques have been used to calculate the surface structures and the stability of quartz and wollastonite, and their adsorption behaviour in the presence of molecular and dissociative water, and the two widely used collector head group molecules of methanoic acid and methylamine. The dissolution behaviour of wollastonite has also been modelled. The calculated surface energy, hydration energy and reaction energy values have been examined and discussed in the light of flotation literature. These studies have given an insight into the interactions at atomic level, which indicate that modelling techniques should be capable of predicting the adsorption behaviour and to design the selective collector molecules, which is of central importance to the mineral processing technique of flotation.

Jan 1, 2005

By Brown GA

Results are presented which demonstrate the feasibility of employing electrolytic membrane technology to process leach liquors derived from alkaline pressure leaching of scheelite concentrates and to recover and recyle sodium carbonate. Thus the problem of disposal of sodium sulphate is avoided. In a further application of the technique sodium tungstate is converted to tungstic acid which can be further processed by three possible routes to crystalline or amorphous tungstic acid or tungsten powder. In each route sodium hydroxide is produced which on carbonation can be recycled as soda ash to the pressure leach stage. Further testwork is required to determine long term operational conditions in the membrane cell and to confirm the effect and deportment of impurities on products. The process has been patented.

Jan 1, 1986

By M McCarthy

Attraction, recruitment and retention of quality mining engineers is becoming increasingly difficult for many mining companies. Part of the problem is attracting young professionals, especially given the decline in graduating engineer numbers, and the other is balancing the new engineerÆs development with business needs. The evolution of the graduate program at Olympic Dam over the last five years has resulted in substantial benefits for both the engineer and the company. The program has developed to provide structured exposure to key areas of the mine enabling new engineers to step into vacated roles as the need arises. The pool of quality engineers generated by the graduate program is a buffer against high industry turnover and helps reduce future recruitment expenditure. Olympic DamÆs program goes beyond conventional recruitment of graduate engineers. Innovations designed to improve intake include the employment of graduate engineers as well as final year students, retraining of existing personnel from other backgrounds and fast track recruitment for previous vacation students. By employing a cross-section of professionals to complement the generic university graduate, the company takes full advantage of the relevant lifestyle experience belonging to the individual, which is a substantial factor in turnover. Study assistance and a salary paid for final year students and mature age students often creates a loyalty that lasts beyond graduation. Careful selection of vacation students increases the ease of recruitment at a later stage and ensures that full advantage is taken of the relationship developed previously between the company and young professional. The evolution of recruitment at Olympic Dam has seen a decline in the turnover statistics of young mining professionals.

Jan 1, 2005

Current mine ventilation systems have evolved from simple, limited energy, series or multi split layouts motivated by low suction, slow running, surface fans. Concentration of coal production from fewer working places and ventilation splits, and varying needs, hazards and challenges, however, have led to substan- tial changes. Modern ventilation systems, therefore, are more complex, sometimes more interdependent on others, more energy intensive, and are founded on the use of multiple airways and greater suction, higher speed surface ventilators and often booster fans. Intensi- fication of output has resulted also in higher gas emission rates, the wide adoption of fire- damp drainage, and sometimes in particular problems such as spontaneous firedamp emissions. Some coal mines are subject to spontaneous outbursts of coal and firedamp. These and related matters and current practices and developments are leading to discernible trends, potential advances, and further changes in Practice.

Jan 1, 1983

By J St George

Much of AucklandÆs transport infrastructure has been developed on surface with little or no consideration of underground options. Current and planned transportation routes are now facing high costs due to land values and increasing environmental resistance to surface development. The option of utilising underground space becomes a feasible investment decision for these links as well as being the only option to develop the rail network within the inner city area. Transportation tunnels offer a quieter, more energy efficient means of getting around with minimal impacts on the surface environment. One of the major impediments to tunnelling is the high construction cost, which is partly related to the risks of encountering unexpected ground conditions and/or the possibility of causing surface ground deformations which could damage structures. The geology of Auckland has had substantial investigation through various studies and projects. The sediments of the East Coast Bays Formation (ECBF) underlie most of the Auckland urban area. It is classified as a soft rock and is a suitable material to tunnel through using either a tunnel boring machine or a roadheader. This paper reviews the limited amount of tunnelling completed in the urban Auckland area, together with the international advancements that have been made in the tunnelling industry. From the known features of the local geology and the problems encountered historically, the likely risks of tunnelling in Auckland are presented and ways in which those risks could be reduced and managed, are discussed. In addition, contractual arrangements between client and contractor are assessed with respect to complicated projects (such as tunnelling), so that the risks can be managed to create efficient infrastructure routes with reduced costs.

Jan 1, 2008

Recent well-publicised problems with the start-up of new mining projects have continued to feed the perception that the mining business in general and Ore Reserves in particular are a poor risk. New mines commonly experience difficulties when the true variability of ore characteristics becomes apparent during commissioning. At this critical stage, the impact of lower metal recovery, reduced throughput or increased consumption of reagents and energy can have a catastrophic effect on economic returns, as illustrated by the premature closure of some operations. There appear to be several common reasons contributing to the poor performance of mining projects, of which three are examined here: lack of early risk assessment before feasibility studies are started, inadequate sampling for metallurgical test work and variability of the run-of-mine (ROM) ore. An underlying feature of these issues is the lack of effective interaction between geologists, mining engineers and metallurgists/ process engineers. Geologists need to be more aware of ore processing issues and the range of characteristics that need to be considered as part of the resource estimate. Metallurgists need a greater understanding of the variability of the run of mine ore in terms of all the characteristics that influence the design and operation of the plant. Mining engineers need to determine the short-term variability of the ore in the mine schedule, so that there is confidence that the quality of the run-of-mine ore will be within the design specifications of the plant. A substantial overlap between these disciplines and sharing of areas of responsibility is necessary if these and other technical problems are to be better understood, production estimates are to be improved and commercial risks are to be reduced. Although the JORC Code (1999) provides guidelines for reporting all the issues that are material to an Ore Reserve estimate, some issues are rarely fully addressed in Ore Reserve reports. In particular there is no formal requirement for a metallurgist to assure his or herself of the appropriateness of the Ore Reserve classification. Consequently the level of uncertainty related to recovered grade and ore processing characteristics may be understated. It is suggested that to meet the concerns of bodies funding new mineral developments a stronger multi-disciplinary approach to the analysis of mineral deposits and reporting of Ore Reserves is required. The culmination of this approach would be the formal requirement for a geologist, mining engineer and a metallurgist to co-sign Ore Reserve reports.

Jan 1, 2002